Compressor bypass flow arrangement

ABSTRACT

Methods and devices are disclosed for introducing a compressor bypass flow that is returned from location that is downstream of a pressure source of an internal combustion engine to an air filter housing that is located upstream of the pressure source.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of PCT Application No.PCT/US18/18119, filed Feb. 14, 2018, which claims priority to U.S.Provisional Application Ser. No. 62/458,809 filed on Feb. 14, 2017, eachof which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to internal combustion engines,and more particularly to systems, devices and methods for re-introducinga compressor bypass flow into an air filter housing upstream of aturbocharger of the internal combustion engine.

BACKGROUND

Some internal combustion engines include turbochargers with a compressorto compress intake air. Fuel can be added upstream of the compressor forcompression and mixing with the intake flow. In addition, somecompressors include a bypass in which excess or rejected compressedintake air from the downstream system and fuel (compressor bypass (CBP)flow) are returned from downstream of the compressor to upstream of thecompressor. Other systems return high pressure combustion gases thatescape between the pistons and cylinders (also known as blow-by orclosed crankcase ventilation (CCV) gases) upstream of the compressor toprevent the release of these gases to atmosphere. However, presentsystems separately return CCV gases and CBP flow directly to the intakepiping and/or other locations that may disturb the flow to theturbocharger so that engine performance and transient response arenegatively impacted. In addition, introducers for CBP flow can be bulkyand expensive to manufacture and implement. Therefore, furtherimprovements in this technology area are needed.

SUMMARY

One embodiment is a unique system, method and/or apparatus forintroducing a CBP flow at or upstream of an internal combustion engineand/or upstream of an inlet to a pressure source, such as a compressorof an engine turbocharger. In a specific embodiment, the apparatusincludes an air filter housing in the intake system with at least oneinlet for receiving the CBP flow, at least one inlet for receiving afresh airflow, and at least one outlet for providing a mixture of thereturned CBP flow and filtered fresh airflow to the pressure source.

In a further embodiment, the air filter housing includes first andsecond outlets connected to respective ones of first and secondturbochargers. Air-fuel mixers are provided between each of the outletsand respective ones of the first and second turbochargers to providefuel and form charge flows that are provided to the first and secondturbochargers for compression. The compressed charge flows are combinedand provided to a charge air cooler and then a portion of the cooled,compressed charge flow is returned to the air filter housing through abypass line connected downstream of the charge air cooler and upstreamof an intake throttle.

This summary is not intended to identify key or essential features ofthe claimed subject matter, nor is it intended to be used as an aid inlimiting the scope of the claimed subject matter. Further embodiments,forms, objects, features, advantages, aspects, and benefits shall becomeapparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The description herein makes reference to the accompanying drawingswherein like numerals refer to like parts throughout the several views,and wherein:

FIG. 1 is a schematic block diagram of one embodiment of an internalcombustion engine and turbocharger system.

FIGS. 2A and 2B are schematic block diagrams of the air filter assemblyfor the internal combustion engine and turbocharger system of FIG. 1.

FIG. 3 is a flow diagram of a procedure for returning compressor bypassflow.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, any alterations and further modificationsin the illustrated embodiments, and any further applications of theprinciples of the invention as illustrated therein as would normallyoccur to one skilled in the art to which the invention relates arecontemplated herein.

FIG. 1 is a schematic block diagram of one embodiment of a system 10with an internal combustion engine 12 and a pressure source such as afirst turbocharger 14 a and a second turbocharger 14 b. Embodiments alsocontemplate a single turbocharger, or more than two turbochargers. Thesystem 10 includes an air filter assembly 16 to provide a source offiltered intake fresh airflow 24 and a CBP flow 25 to engine 12 throughthe pressure source, such as through compressors 20 a, 20 b ofturbochargers 14 a, 14 b. The turbochargers 14 a, 14 b also each includea turbine 22 a, 22 b connected to the associated compressor 20 a, 20 bwith a respective shaft 21 a, 21 b, and also connected to an associatedexhaust system 26 a, 26 b to drive turbine 22 a, 22 b and thus eachcompressor 20 a, 20 b with exhaust flows 27 a, 27 b.

In the illustrated embodiment, the pressure source includes compressors20 a, 20 b of turbochargers 14 a, 14 b, however, in other embodimentsthe pressure source can be a positive displacement supercharger, adynamic compression supercharger, and/or any other device capable ofreceiving and outputting the charge flow 50 a, 50 b with increasedpressure. It is also contemplated that multiple turbochargers can beincluded to provide high pressure and low pressure turbocharging stagesthat compress the intake flow.

Each compressor 20 a, 20 b receives a corresponding charge flow 50 a, 50b from a respective air-fuel mixer 52 a, 52 b. Each air-fuel mixer 52 a,52 b is connected to a fuel source (not shown) to provide fuel formixing with the combined fresh airflow 24 and CBP flow 25 from airfilter assembly 16. The mixture forms a charge flow 50 a, 50 b includingat least fresh airflow 24, CBP flow 25 and fuel. Compressors 20 a, 20 beach outlet a respective pressurized charge flow 54 a, 54 b whichcombine to provide a pressurized charge flow 56 to charge air cooler 30.

Air-fuel mixers 52 a, 52 b are provided at the inlet or on an upstreamside of the respective compressor 20 a, 20 b. Furthermore, thecompressors 20 a, 20 b can be in flow communication with intercooler orcharge air cooler 30. Charge air cooler 30 is located betweencompressors 20 a, 20 b and an intake throttle 58.

The engine 12 includes cylinders 13 connected to an intake manifold 60to receive at least a portion of the charge flow 56 from intake throttle58. Cylinders 13 are connected to exhaust systems 26 a, 26 b to releaseexhaust gases produced by combustion of the charge flow 56 in thecylinders 13. Exhaust systems 26 a, 26 b may provide exhaust gases tothe respective turbochargers 14 a, 14 b.

In the illustrated embodiment, the engine 12 includes four cylinders 13in an in-line arrangement. However, the number of cylinders 13 may beany number, and the arrangement of cylinders 13 may be any arrangement,including V-shaped, and is not limited to the number and arrangementshown in FIG. 1. The system 10 can further include an exhaust gasrecirculation system (not shown) which recirculates a portion of exhaustflows 27 a, 27 b that mixes upstream and/or downstream of turbochargers14 a, 14 b.

The internal combustion engine 12 can be a diesel engine, a gasolineengine, a dual fuel engine, or any other type of internal combustionengine 12. In certain embodiments, the engine 12 can be a spark-ignitedengine that uses a gaseous fuel such as, for example, natural gas,bio-gas, commercially available gas, methane, ethane, propane (LPG),butane, ethanol, producer gas, field gas, nominally treated field gas,well gas, nominally treated well gas, liquefied natural gas (LNG),compressed natural gas, landfill gas, condensate, coal-bed methane(CBM), liquid fuels that are readily vaporized (such as gasoline), andmixtures of these. However, other types of fuels are not precluded, suchas any suitable liquid fuel and gaseous fuel. In other embodiments,engine 12 includes a lean combustion engine such as a diesel cycleengine that also uses a liquid fuel such as diesel fuel. Engine 12 canbe used in stationary applications, such for power generationapplications when coupled with a generator, or for powering equipmentsuch as in mining applications, etc. Other applications are alsocontemplated and not precluded, such as vehicular applications.

Engine intake manifold 60 distributes the charge flow 56 that is notrecirculated as CBP flow 25 to cylinders 13 of engine 12. Exhaustsystems 26 a, 26 b are also coupled to engine 12 with engine exhaustmanifold portions 62 a, 62 b associated with a respective subset of thecylinders 13. Each exhaust system 26 a, 26 b may include an exhaustconduit 64 a, 64 b extending from exhaust manifold 62 a, 62 b to arespective turbine 22 a, 22 b. Each turbine 22 a, 22 b may include avalve such as controllable wastegate 66 a, 66 b or other suitable bypassthat is operable to selectively bypass at least a portion of the exhaustflow from the associated turbine 22 a, 22 b to reduce boost pressure,charge flow and engine torque under certain operating conditions. Inanother embodiment, turbine 22 a, 22 b is a variable geometry turbinewith a size-controllable inlet opening. While specific examples havebeen discussed, no particular form of intake or exhaust control valvingis required, nor is the use of the same precluded.

An aftertreatment system (not shown) can be connected with an outletconduit 54 of each of the exhaust systems 26 a, 26 b or after theexhaust flows are combined (not shown). The aftertreatment system mayinclude, for example, oxidation devices (DOC), particulate removingdevices (DPF, CDPF), constituent absorbers or reducers (SCR, AMOX, LNT),reductant systems, and other components if desired.

Referring further to FIGS. 2A-2B, air filter assembly 16 may furtherinclude a compressor bypass inlet 70 that is connected to a compressorbypass line 72 that is connected downstream of or at an outlet side ofcharge air cooler 30 and upstream of intake throttle 58. Compressorbypass line 72 may further include a CBP control valve 74 to control CBPflow 25 to air filter assembly 16. CBP valve 74 can be selectivelyopened and closed to allow CBP flow 25 to be returned to the air filterassembly 16 to reduce compressor surge under certain operatingconditions, such as when an intake throttle 58 is closed. System 10 mayfurther include a crankcase ventilation line 76 connected to engine 12to return blow-by or crankcase ventilation gases to air filter assembly16.

Charge air cooler 30 can be located downstream from compressors 20 a, 20b and upstream of the location in which compressor bypass 72 isconnected to return the CBP flow 25. Charge air cooler 30 may embody,for example, an air-to-air heat exchanger, an air-to-liquid heatexchanger, or a combination of both to facilitate the transfer ofthermal energy to or from the charge flow 56 directed to engine 12. Thearrangement can differ for a V-shaped engine where each cylinder bank isconnected to an inlet supply conduit that includes a turbocharger and/orthrottle downstream of a charge air cooler. Multiple throttle valves canalso be provided in the inlet supply conduit downstream and/or upstreamof the charge air cooler.

Compressors 20 a, 20 b may be fixed or variable geometry compressorsconfigured to receive charge flows 52 a, 52 b and compress the flows toa predetermined pressure level before engine 12. The charge flow 52 a,52 b is pressurized with the respective compressor 20 a, 20 b andcombined to provide a pressurized, combined charge flow 56 that is sentthrough charge air cooler 30 and supplied to engine 12 through intakethrottle 58 to engine intake manifold 60.

Referring to FIGS. 2A-2B, one embodiment of air filter assembly 16includes an air filter housing 100 with inlets 102 a, 102 b forreceiving fresh airflow 24. Air filter housing 100 also housesside-by-side air filter arrangements 104 a, 104 b for receiving thefresh airflow 24 and filtering the fresh air flow to provide thecombined fresh airflow 24 and CBP flow 25 to respective ones of firstand second outlets 106 a, 106 b connected to respective ones of theair-fuel mixers 52 a, 52 b. In one embodiment, each filter arrangement104 a, 104 b includes two air filters stacked one upon the other asshown in FIG. 2A.

Each air filter assembly 16 also includes CBP inlet 70 for providing CBPflow 25 to air filter housing 100 from CBP line 72. In one embodiment,the CBP inlet is provided on a different side of the air filter housing100 than inlets 102 a, 102 b. In a further embodiment, a CCV inlet 71 isprovided to also connect a CCV line 76 to return crankcase ventilationgases from engine 12 to air filter assembly 16. CCV inlet 71 can be onthe same side of housing 100 as CBP inlet 70. By returning the CBP flow25 directly to air filter housing rather than to another location in theintake system plumbing, the CBP flow 25 does not disturb the flow intothe compressors 20 a, 20 b. In addition, the CBP flow 25 is evenlydistributed and avoids variations across the turbochargers 14 a, 14 b.

In certain embodiments, the air filter assembly 16 may include a numberof features not shown in FIG. 1, including an air filter(s), noisereduction and flow altering devices, such as, but not limited to,baffles. In another example, a flow meter, such as mass airflow sensor(MAF), can be disposed upstream of the compressor 20, such as at or neara compressor inlet. In addition, one or more sensors that measuretemperature, humidity, pressure, pressure change, can be disposed at ornear the compressor inlet.

Various aspects of the present disclosure are contemplated. One aspectis directed to a procedure for returning a compress bypass flow is shownin FIG. 3. Procedure 300 includes an operation 302 to receive a freshairflow in a flow passage into an air filter housing upstream of aninternal combustion engine. Procedure 300 continues at operation 304 toreceive a compressor bypass flow into the air filter housing. Fromoperation 304, procedure 300 continues at operation 306 to deliver thefresh airflow and the compressor bypass flow from the air filter housingto an air-fuel mixer.

Procedure 300 continues at operation 308 to introduce a fuel into theair-fuel mixer to combine with the fresh air flow and the compressorbypass flow to provide a charge flow. From operation 308 procedure 300continues at operation 310 to pressurize the charge flow downstream ofthe air-fuel mixer. The compressor bypass flow that is returned atoperation 304 is a portion of the pressurized charge flow from operation310.

In one embodiment, the charge flow is pressurized at operation 310 by acompressor of a turbocharger. In a further embodiment, the pressurizedcharge flow is cooled by a charge air cooler downstream of theturbocharger and the returned portion of the pressurized charge flow istaken downstream of the charge air cooler and upstream of an intakethrottle.

In another embodiment, operation 306 includes delivering the freshairflow and the compressor bypass flow from the air filter housing tofirst and second fuel mixers. Operation 308 includes introducing thefuel into each of the first and second fuel mixers to provide first andsecond charge flows. Operation 310 includes pressurizing the first andsecond charge flows with respective ones of first and second compressorsof first and second turbochargers. In a further embodiment of theprocedure, the first and second charge flows from the first and secondcompressors are combined upstream of a charge air cooler. In yet afurther embodiment, a portion of the combined first and second chargeflows from a location downstream of the charge air cooler and upstreamof an intake throttle to the air filter housing is returned to providethe compressor bypass flow.

According to another aspect, a system includes at least one pressuresource including an inlet and an outlet. The at least one pressuresource is operable to pressurize a charge flow received by the pressuresource through the inlet and to provide the pressurized portion of thecharge flow to the outlet. The system includes an air filter housingincluding at least one air filter housed therein. The air filter housingincludes at least one outlet, and the at least one outlet is connectedto the inlet of the at least one pressure source. The air filter housingalso includes a first inlet for receiving a fresh airflow and a secondinlet for receiving a compressor bypass flow that is returned from alocation downstream of the at least one pressure source. The freshairflow and compressor bypass flow combine in the air filter housing andare provided to the at least one pressure source through the at leastone outlet.

In one embodiment, the system includes a fuel mixer between the airfilter housing and the at least one pressure source, and the fuel mixeris connectable to a fuel source. In a refinement of this embodiment, thesystem includes a charge air cooler downstream of the pressure sourceand an intake throttle downstream of the charge air cooler. The secondinlet of the air filter housing is connected to a bypass line thatextends to an outlet located between the charge air cooler and theintake throttle. In a further refinement, the bypass line includes acontrol valve to control the compressor bypass flow.

In another embodiment, the at least one outlet of the air filter housingincludes a first outlet and a second outlet, and the at least onepressure source includes a first turbocharger and a second turbocharger,and each of the first and second turbochargers is connected to arespective one of the first and second outlets. In a refinement of thisembodiment, the system includes a first fuel mixer between the firstoutlet and the first turbocharger and a second fuel mixer between thesecond outlet and the second turbocharger. In a further refinement, thesystem includes a charge air cooler connected to outlets of the firstand second turbochargers and an intake throttle downstream of the chargeair cooler. In still a further refinement, the second inlet of the airfilter housing is connected to a bypass line that extends to an outletlocated between the charge air cooler and the intake throttle. In afurther refinement, the bypass line includes a control valve to controlthe compressor bypass flow.

According to yet another aspect, an air filter assembly is provided thatincludes an air filter housing with at least one air filter housedtherein. The air filter housing includes at least one outlet that isconnected to an inlet of a pressure source that is operable topressurize a charge flow to an internal combustion engine. The airfilter housing includes a first inlet for receiving a fresh airflow anda second inlet for receiving a compressor bypass flow that is returnedfrom a location downstream of the at least one pressure source. Thefresh airflow and compressor bypass flow combine in the air filterhousing and are passed through the at least one outlet to the pressuresource.

In one embodiment, the at least one outlet of the air filter housingincludes a first outlet and a second outlet connectable to respectiveones of a first turbocharger and a second turbocharger. In anotherembodiment, the second inlet of the air filter housing is connected to abypass line that extends to a location between a charge air cooler andan intake throttle. In yet another embodiment, the air filter housingincludes a third inlet connected to a crankcase ventilation line forreturning crankcase ventilation gases from an engine to the air filter.In still another embodiment, the at least one air filter includes firstand second air filters in side-by-side relation.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly certain exemplary embodiments have been shown and described andthat all changes and modifications that come within the spirit of theinventions are desired to be protected. In reading the claims, it isintended that when words such as “a,” “an,” “at least one,” or “at leastone portion” are used there is no intention to limit the claim to onlyone item unless specifically stated to the contrary in the claim. Whenthe language “at least a portion” and/or “a portion” is used the itemcan include a portion and/or the entire item unless specifically statedto the contrary.

What is claimed is:
 1. A method, comprising: receiving a fresh airflowin a flow passage into an air filter housing upstream of an internalcombustion engine; receiving a compressor bypass flow into the airfilter housing; delivering the fresh airflow and the compressor bypassflow from the air filter housing to a first air-fuel mixer and a secondair-fuel mixer; introducing a fuel into each of the first and secondair-fuel mixers to combine with the fresh air flow and the compressorbypass flow to provide a first charge flow and a second charge flow; andpressurizing the first charge flow and the second charge flow downstreamof the first air-fuel mixer and the second air-fuel mixer withrespective ones of first and second compressors of first and secondturbochargers, wherein the compressor bypass flow is a returned portionof the pressurized first and second charge flows.
 2. The method of claim1, wherein receiving the compressor bypass flow in the air filterhousing includes receiving the compressor bypass flow through an inletinto the air filter housing that is separate from an inlet of the airfilter housing that receives the fresh airflow.
 3. The method of claim1, wherein the charge flow is pressurized by a compressor of aturbocharger.
 4. The method of claim 3, wherein the pressurized chargeflow is cooled by a charge air cooler downstream of the turbocharger andthe returned portion of the pressurized charge flow is taken downstreamof the charge air cooler and upstream of an intake throttle.
 5. Themethod of claim 1, further comprising combining the first and secondcharge flows from the first and second compressors upstream of a chargeair cooler.
 6. The method of claim 5, further comprising returning aportion of the combined first and second charge flows from a locationdownstream of the charge air cooler and upstream of an intake throttleto the air filter housing to provide the compressor bypass flow.
 7. Asystem, comprising: at least one pressure source including an inlet andan outlet, the at least one pressure source operable to pressurize acharge flow received by the pressure source through the inlet and toprovide the pressurized portion of the charge flow to the outlet; an airfilter housing including at least one air filter housed therein, the airfilter housing including at least one outlet, the at least one outletconnected to the inlet of the at least one pressure source, the airfilter housing including: a first inlet for receiving a fresh airflow;and a second inlet for receiving a compressor bypass flow that isreturned from a location downstream of the at least one pressure source,wherein the fresh airflow and compressor bypass flow combine in the airfilter housing and are provided to the at least one pressure sourcethrough the at least one outlet; wherein the at least one outlet of theair filter housing includes a first outlet and a second outlet, and theat least one pressure source includes a first turbocharger and a secondturbocharger, and each of the first and second turbochargers isconnected to a respective one of the first and second outlets.
 8. Thesystem of claim 7, further comprising a fuel mixer between the airfilter housing and the at least one pressure source, the fuel mixerbeing connectable to a fuel source.
 9. The system of claim 8, furthercomprising a charge air cooler downstream of the pressure source and anintake throttle downstream of the charge air cooler, wherein the secondinlet of the air filter housing is connected to a bypass line thatextends to an outlet located between the charge air cooler and theintake throttle.
 10. The system of claim 9, wherein the bypass lineincludes a control valve to control the compressor bypass flow.
 11. Thesystem of claim 7, further comprising a first fuel mixer between thefirst outlet and the first turbocharger and a second fuel mixer betweenthe second outlet and the second turbocharger.
 12. The system of claim11, further comprising a charge air cooler connected to outlets of thefirst and second turbochargers and an intake throttle downstream of thecharge air cooler.
 13. The system of claim 12, wherein the second inletof the air filter housing is connected to a bypass line that extends toan outlet located between the charge air cooler and the intake throttle.14. The system of claim 13, wherein the bypass line includes a controlvalve to control the compressor bypass flow.
 15. The system of claim 7,wherein the first inlet and the second inlet are provided on differentsides of the air filter housing.
 16. An air filter assembly, comprising:an air filter housing including at least one air filter housed therein,the air filter housing including at least one outlet, the at least oneoutlet connected to an inlet of a pressure source that is operable topressurize a charge flow to an internal combustion engine, the airfilter housing including: a first inlet for receiving a fresh airflow;and a second inlet for receiving a compressor bypass flow that isreturned from a location downstream of the at least one pressure source,wherein the fresh airflow and compressor bypass flow combine in the airfilter housing and are passed through the at least one outlet to thepressure source, wherein the at least one outlet of the air filterhousing includes a first outlet and a second outlet connectable torespective ones of a first fuel mixer connectable to a firstturbocharger and a second fuel mixer connectable to a secondturbocharger, and the second inlet of the air filter housing isconnected to a bypass line that extends to a location between a chargeair cooler that receives compressed charge flow from the first andsecond turbochargers and an intake throttle.
 17. The assembly of claim16 wherein the air filter housing includes a third inlet connected to acrankcase ventilation line for returning crankcase ventilation gasesfrom an engine to the air filter.
 18. The assembly of claim 16, whereinthe at least one air filter includes first and second air filters inside-by-side relation.